Various drugs have been administered orally or parenterally, e.g. by intravenous (IV), intramuscular (IM) or subcutaneous (subcu) injection. Injection of a drug can be effective, but is often characterized by patient discomfort and inconvenience, and thus poor patient compliance. As a result, it is often considered desirable to provide a medicament in an oral formulation, as an alternative to, or substitute for, injection. However, oral formulations are often characterized by poor absorption, rapid first-pass metabolism in the liver, slow attainment of effective blood plasma levels and other problems.
Intranasal formulations have been used for delivery of some medicaments. Nasal preparations are generally administered in metered sprays having volumes of less than 25 μl, preferably less than 150 μl, and ideally from 25 to 100 μl, since administration of larger volumes usually exceeds the capacity of the nasal sinuses and results in volumes in excess of about 250 μl bypassing the sinuses and flowing down the back of the throat where it is swallowed. As smaller dose volumes are preferred for nasal administration, poor water solubility of many compounds limits the dose that may be administered to a patient at any given time. This in turn limits the clinical effectiveness of nasally-administered medicaments.
There is a need for formulations that are capable of providing to the nasal mucosa sufficient quantity of active pharmaceutical agents in a small enough volume to provide therapeutically effective blood plasma concentration of active pharmaceutical agent within a short period after administration of the formulation to the nasal mucosa. These and other objects and advantages are provided by the invention described herein.